MOTOR FUNCTIONS OF CEREBRAL CORTEX OF CAT 187 



of the field. The portion of the field extending between the 

 upper end of the fissura rhinalis and the outer half of the crucial 

 sulcus gave movements of the head and neck only. 



Summary. To make a generalized account of the fields, the 

 total stimulable areas have been combined, and also the sepa- 

 rate areas for the anatomically segmental movements, for the 

 hemispheres of all animals (figs. 4, 5, 6, 7, and 8). It is found 

 that the motor field as a whole, figure 4, extends from the ante- 

 rior end of the fissura lateralis anteriorly to a line about 0,5 

 cm. above the olfactory lobe, and from the fissura coronalis in- 

 wards to the median line. In front of the crucial sulcus it ex- 

 tends over the median margin, a short distance on the median 

 surface of the hemisphere. The areas for the movement of the 

 several body segments are not distinct but overlap, the stimu- 

 lation of the posterior one-fifth of the field giving almost entirely 

 movements of the hind limb and tail, stimulation of the anterior, 

 inner portion almost entirely movements of the head and neck. 

 Between these areas the fields overlap, but it may be said that 

 the cortical representations, for the different body areas, occupy 

 the following fields: 



(1) Movements of the hind limb (fig. 6), a field about four- 

 fifths the size of the entire motor area and extending from the 

 median line almost to the fissura coronalis, and from a line, 

 slightly internal to the anterior end of the fissura lateralis, to a 

 line half way from the sulcus cruciatus to the upper extremity 

 of the olfactory lobe. This field is almost hexagonal in shape 

 and only touches the median line adjacent to the sulcus cruciatus. 

 The larger portion of this field is posterior to the sulcus cruciatus. 

 (2) Movements of the trunk and tail (fig. 8) , small scattered areas 

 lying within the posterior portion of the hind limb field. (3) 

 Movements of the fore limb (fig. 7), an octagonal shaped field 

 almost as large as the hind limb field, and extending from a 

 line half way between the anterior end of the fissura lateralis 

 and the sulcus cruciatus anteriorly, to the upper end of the 

 fissura rhinalis and laterally from the fissura coronalis to within 

 a short distance of the median line. It approaches nearest to 

 the median line anterior to the sulcus cruciatus, and from there 



